Skate boot

ABSTRACT

A skate boot includes a foot portion configured to receive and secure a foot of a wearer. The skate boot includes a first tendon guard positioned proximal an Achilles tendon of a wearer of the skate boot, the first tendon guard being connected to the foot portion at a first articulation point and adjacent the foot portion along a medial abutment line and a lateral abutment line. The skate boot may optionally include a second tendon guard connected to the foot portion at a second articulation point and to the first tendon guard, the second tendon guard covering the first articulation point. In at least one embodiment, an elastomeric band is connected to the foot portion and to the first tendon guard and configured to bias the first tendon guard to a closed position. In at least one embodiment, an electrical generator is provided to heat an ice skate interconnected to the boot.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of U.S. Provisional PatentApplication No. 60/978,758 filed on Oct. 10, 2007, entitled “SkateBoot,” the entire disclosure of which is incorporated herein byreference in its entirety for all purposes.

FIELD

The present invention relates generally to ice skates and morespecifically to the construction of the rigid support component of theskate boot, traditionally referred to as the sole and counter of theboot.

BACKGROUND

Skating locomotion is based on propulsion through a glide technique. Theskate blade that is performing the push glides at a right angle to thedirection of the push force (Boer et al., 1986; Boer et al., 1989; vanIngen Schenua et al., 1980; van Ingen Schenua et al., 1985, van IngenSchenua at al., 1987). This causes the trajectory of the body to looklike a sine wave (Boer et al., 1986; Deloij et al., 1986). The motion ofone leg during skating involves a glide phase, a push phase, and arecovery phase (Allinger and Motl, 2000). The push phase is the onlyphase where the generation of velocity occurs.

Nothing herein is to be construed as an admission that the presentinvention is not entitled to antedate a publication by virtue of priorinvention. Furthermore, the dates of publication where provided aresubject to change if it is found that the actual date of publication isdifferent from that provided here.

SUMMARY

One or more inventions are described herein. In one embodiment, a skateboot is provided that includes a foot portion configured to receive andsecure a foot of a wearer. The skate boot includes a first tendon guardpositioned proximal an Achilles tendon of a wearer of the skate boot,the first tendon guard being connected to the foot portion at a firstarticulation point and adjacent the foot portion along a medial abutmentline and a lateral abutment line. The skate boot may optionally includea second tendon guard connected to the foot portion at a secondarticulation point and to the first tendon guard, the second tendonguard covering the first articulation point. In at least one embodiment,an elastomeric band is connected to the foot portion and to the firsttendon guard and configured to bias the first tendon guard to a closedposition. In at least one embodiment, an electrical generator isprovided to heat an ice skate interconnected to the skate boot.

It is to be understood that the present invention includes a variety ofdifferent versions or embodiments, and this Summary is not meant to belimiting or all-inclusive. This Summary provides some generaldescriptions of some of the embodiments, but may also include some morespecific descriptions of certain embodiments. As used herein, “at leastone”, “one or more”, and “and/or” are open-ended expressions that areboth conjunctive and disjunctive in operation. For example, each of theexpressions “at least one of A, B and C”, “at least one of A, B, or C”,“one or more of A, B, and C”, “one or more of A, B, or C” and “A, B,and/or C” means A alone, B alone, C alone, A and B together, A and Ctogether, B and C together, or A, B and C together.

It is to be noted that the term “a” or “an” entity refers to one or moreof that entity. As such, the terms “a” (or “an”), “one or more” and “atleast one” can be used interchangeably herein. It is also to be notedthat the terms “comprising”, “including”, and “having” can be usedinterchangeably.

Various embodiments of the present invention are set forth in theattached figures and in the detailed description of the invention asprovided herein and as embodied by the claims. It should be understood,however, that this Summary does not contain all of the aspects andembodiments of the present invention, is not meant to be limiting orrestrictive in any manner, and that the invention as disclosed herein isand will be understood by those of ordinary skill in the art toencompass obvious improvements and modifications thereto.

Additional advantages of the present invention will become readilyapparent from the following discussion, particularly when taken togetherwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

To further clarify the below and other advantages and features of thepresent invention, a more particular description of the invention willbe rendered by reference to specific embodiments thereof which areillustrated in the appended drawings. It is appreciated that thesedrawings depict only typical embodiments of the invention and aretherefore not to be considered limiting of its scope. The invention willbe described and explained with additional specificity and detailthrough the use of the accompanying drawings in which:

FIG. 1A illustrates an embodiment of an articulating tendon guard from asagittal view according to one embodiment of the invention.

FIG. 1B is a rear view of the articulating tendon guard illustrated inFIG. 1A.

FIG. 2A is a top view of the primary tendon guard and neoprene strap ofthe embodiment of FIG. 1A.

FIG. 2B is a sagittal view of the primary tendon guard and neoprenestrap of the embodiment of FIG. 1A.

FIG. 3A illustrates a an articulating tendon guard from a sagittal viewaccording to a further embodiment of the invention.

FIG. 3B is a rear view of the articulating tendon guard illustrated inFIG. 3A.

FIG. 3C is another sagittal view of the embodiment of FIG. 3A. In FIG.3C the skate boot is illustrated with the tendon guards in an ankleplantar flexed position.

FIG. 4A illustrates an articulating tendon guard according to anotherexample embodiment of the invention.

FIG. 4B is a sagittal view of the articulating tendon guard of FIG. 4Awith the tendon guards in an ankle plantar flexed position.

FIG. 4C is a sagittal view of the articulating tendon guard of FIG. 4Awith the tendon guards in an ankle dorsi flexed position.

FIG. 5 is a photograph of the Graf Supra 703 (left), and the CCM 952Super Tacks (right), showing maximal ankle extensions (plantar flexion).The ankle joint axis is marked by dot 18, and the knee joint axis ismarked by a dot 19.

FIG. 6 is a photograph of the Graf Supra 703 modified for the ankleextension (left), and the CCM 952 Super Tacks modified with a removedupper tendon guard (right), showing maximal ankle extension (plantarflexion). The ankle joint axis is marked by a dot 18, and the knee jointaxis is marked by a dot 19.

FIG. 7 is a photograph of a bare foot showing three successive ankleextension positions. The ankle axis of rotation is marked by a dot 18.

FIG. 8 is a photograph of a VH stock custom speed skate showing maximalankle extension (plantar flexion). The ankle joint axis is marked by adot 18, and the knee joint axis is marked by a dot 19.

FIG. 9 is a schematic of a speed skating push with the pivot pointpositioned in the same place as the end of the hockey skate blade, and aschematic of a hockey skating push. Rigid links were created between thehip joint, knee joint, ankle joint, and the point where rotation of thefoot occurs (pivot point) for biomechanical analysis.

FIG. 10 is photographs showing the data collection set up in thelaboratory.

FIG. 11 is a graph showing the final center of mass velocity for asimulated skating push with a conventional hockey skate and the ankleextension skate. Data presented are averages with 95% confidenceintervals for ten subjects.

FIG. 12 is a graph showing the ankle energy generated during theexplosive push phase for a simulated skating push with a conventionalhockey skate and the ankle extension conversion skate. Data presentedare averages with 95% confidence intervals for ten subjects.

FIG. 13 is a diagram of the gliding direction of the pushing skate,final CM velocity vector, and the component of the CM velocity vector inthe direction of forward motion for the ankle extension conversion skateand the traditional hockey skate.

FIG. 14 is a diagram representing the movement of two hypotheticalhockey players skating maximally towards a puck 12.27 m away. Player 1represents a player wearing the ankle extension conversion skate. Player2 represents a player wearing a traditional hockey skate.

FIG. 15 is photographs of the Graf Supra 703 unmodified, and modifiedfor the ankle extension, during maximal eversion and inversion of theankle joint. Photographs were taken from the frontal view. The center ofthe ankle joint axis is marked by a dot 18, and the center of the kneejoint axis is marked by a dot 19.

DETAILED DESCRIPTION

Reference will now be made to the drawings to describe various aspectsof exemplary embodiments of the invention. It is to be understood thatthe drawings are diagrammatic and schematic representations of suchexemplary embodiments, and are not limiting of the present invention,nor are they necessarily drawn to scale.

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the present invention. Itwill be obvious, however, to one skilled in the art that the presentinvention may be practiced without these specific details. In otherinstances, well-known aspects of skate boots have not been described inparticular detail in order to avoid unnecessarily obscuring the presentinvention.

With reference now to FIGS. 1A and 1B, according to a first exampleembodiment of the invention an articulating tendon guard uses a neoprenelower leg strap 5 to connect the articulating tendon guard to the lowerleg of a wearer. In one embodiment the skate boot has two cuts 2 angleddistally towards the ankle axis of rotation, forming the tendon guard 1between them. The two cuts meet approximately 20 mm shy of each other atthe point of articulation 3. The point of articulation is along the samehorizontal axis as the ankle joint center and therefore allows completeunrestricted plantar flexion of the ankle joint. An elastomeric band 4is inserted between the inner and outer layers of the upper and sewn inplace. The elastomeric band 4 crosses the cut 2 and provides recoil ofthe tendon guard 1, after ankle extension. Also, to ensure adequaterecoil of the tendon guard 1 a lower leg strap 5, which may be made ofneoprene for example, is preferably adhered and stitched 6 to the tendonguard. In one embodiment the strap 5 fastens to the lower leg by a hookand loop attachment 7 on the anterior side of the leg (shin), asillustrated in FIGS. 2A and 2B.

In one example embodiment of the invention the tendon guard is formed bymodifying an existing skate boot by cutting the skate boot at cuts 2 andadding the lower leg strap 5 and elastomeric band 4. In another exampleembodiment the tendon guard is formed separately from the skate boot andattached thereto at articulation point 3 by a method known in the art ofconnecting the selected materials.

Another example embodiment of the invention is illustrated in FIGS. 3A,3B, and 3C. In this embodiment a lower leg strap 5 may optionally beomitted while a secondary tendon guard 10 is added to help protect thearticulation 3 of the primary tendon guard 1. The secondary tendon guard10 is also preferably biased to assist in recoil of the primary tendon.The secondary tendon guard 10 articulates at a point 8 that is between 1cm and 5 cm below the articulation of the primary tendon guard 3. Thesecondary tendon guard 10 is attached to the primary tendon guard 1 atpoint 9 with a connector such as a rivet, bolt and t-nut, and the like.

With reference now to FIGS. 4A-4C, in yet another example embodiment ofthe invention electrical generation components are added to moving partsin the skate boot so that current can be conducted to the blade whereresisters will convert the electric current into heat. It has been shownthat heated blades glide 50-75% better than non-heated blades due toreduced ice friction. Electrical generation component 12 generates acurrent when component 13 slides over it as the tendon guards areextended and then recoiled. Electrical generation component 15 alsogenerates a current when component 14 slides over it as the tongue isflexed forward and then recoiled. The current that is generated isconducted along the wire 16 and is converted into heat by the resistors17 that lie in small recesses in the skate blade.

The following Performance Comparison describes attributes of anembodiment of the present invention in comparison to another device.

Performance Comparison

1. Biomechanical and Performance Aspects of a Skate in Accordance withat least one Embodiment of the Present Invention

The Performance Comparison looked at the performance effects ofincreasing ankle joint range of motion during the skating push withcertain modifications to the tendon guard (ankle extension). Thepurposes of this investigation were:

To compare the total amount of push energy and center of mass velocitygenerated during a skating push with the constraints of a conventionalhockey skate versus that with the reduced constraints of a hockey skatethat incorporates the new ankle extension. These results will then berelated to actual skating kinematics.

To determine if the ankle extension has any deleterious effects on anklesupport, stability, and protection.

Data collection consisted of two parts. The first part was a detailedanalysis of angular energetics and center of mass movement during thepush phase of a simulated skating push. Data were collected on tensubjects in the laboratory while the subjects performed a maximal effortskating push on a modified slide board apparatus. The second part of theinvestigation consisted of two case studies that tested prototypes ofthe ankle extension, on the ice. The case studies involved digitalpicture analysis of ankle inversion and eversion, along with anecdotalfeedback.

The lab testing indicated that there was a strong positive influence, ofthe increased ankle range of motion allowable with the ankle extension,on skating performance. It was shown that the increased energygeneration per push resulted in a higher final velocity of the center ofmass during the push phase. It was further shown that the increasedvelocity would have a significant effect on hockey skating performance.

The case studies revealed no decrease in ankle support and stability,with positive anecdotal feedback relating to the matter.

2. Introduction

The skate boot embodiment analyzed in this testing has a tendon guardthat allows a much larger range of motion at the ankle joint than whatis currently allowed with conventional hockey skate boots. The ankleextension allows for a larger range of motion through increased ankleextension. It was speculated that this increased ankle joint extensionwould result in higher energy generation and a slight elongation of thepush, resulting in increased acceleration and maximal skating velocity.

Purpose

To compare the total amount of push energy and center of mass velocitygenerated during a skating push with the constraints of a conventionalhockey skate versus that with the reduced constraints of a hockey skatethat incorporates the new ankle extension. These results will then berelated to actual skating kinematics.

To determine if the ankle extension has any deleterious effects on anklesupport and stability.

3. Methods

Data collection consisted of two parts. The first part was a detailedanalysis of angular energetics and center of mass movement during thepush phase of a simulated skating push. The second part of theinvestigation consisted of two case studies.

Skates

The hockey skates analyzed were the Graf Supra 703 and the CCM 952 SuperTacks. All skates were commercially available and modified for analysisafter purchase. The Graf Supra 703 skates were initially analyzed formaximal extension angle (FIG. 5), and subsequently modified for theankle extension and tested for maximal extension angle (FIG. 6). The CCM952 Super Tacks were initially analyzed for maximal extension angle(FIG. 5), and subsequently modified for an increased range of motion(FIG. 6), to mimic what has been done commercially to allow forincreased ankle extension (i.e. Graf727, Bauer Supremes, Mission SuperFly). An uninhibited foot was analyzed for anatomical extensioncharacteristics (FIG. 7). A VH Stock Custom speed skate boot was alsoanalyzed for maximal extension angle to provide accurate comparisoninformation between the collected data and the hockey skates (FIG. 8).

FIG. 5 shows an ankle extension angle of 106.5°. This angle was believedto be the common extension angle with conventional hockey skates. FIG. 6shows an extension angle of 122° for the ankle extension. Even in FIG. 6where the upper tendon guard is removed from CCM 952 Super Tacks anextension angle of only 110.5° could be achieved. The reason for the11.5° larger extension angle can be clearly seen in FIG. 7, whererotation occurs through the ankle axis. The ankle axis of rotation runsapproximately through the malleoli (ankle bones). It can be clearly seenthat any rigid structure extending vertically above the ankle axis willinhibit ankle extension, and prematurely end the skating push.Therefore, even with the upper tendon guard cut (FIG. 6) the lowerportion of the tendon guard is still too high to allow full ankle rangeof motion. With the ankle extension the cut in the tendon guard isangled distally towards the ankle axis of rotation, allowing for a lessinhibited ankle extension, and a longer skating push. FIG. 8 shows anankle extension angle of 137°, the maximum allowable with a speed skate.This information was used to extrapolate a skating push with aconventional hockey skate and a hockey skate with the ankle extensionfrom the data.

Subjects

A total of ten male subjects participated in this study. All subjectswere elite level speed skaters. All subjects were free from recent lowerextremity injury or pain. Informed written consent in accordance withthe University of Calgary's Research Ethics Board was obtained from allsubjects.

Angular Energetics and Center of Mass Movement

Angular energetics and center of mass (CM) movements were determined onall ten subjects while using their own klap speed skates. The klap skatepivot point (point of foot rotation) was positioned in the same place asthe end of the hockey skate blade, to create similar pushing mechanics(FIG. 9).

The push phase was analyzed on a modified slide board apparatus togreatly reduce the errors associated with on-ice kinetic and kinematictesting; exact testing methodology used by Van Home and Stefanyshyn. Themodified slide board model was set up as follows: a 20 foot by 4 footmelamin sheet had a small block of wood at one end where the subjectperformed the simulated skating push, from this point the subject slidalong the board until friction stopped him. The slide board was boltedto a force platform, and was surrounded by seven high-speed digitalcameras, at the location of the board where the pushes occurred. Thepushing foot was in a speed skate that had a protective low resistancematerial under the blade, so that the blade and slide board was notdamaged. The contrilateral foot was clad in a running shoe covered witha wool sock. Ten maximal pushes were executed by each subject.

The start of the push phase was defined as the instant when the kneeangular velocity exceeded 90 deg/s, a value previously used in theliterature to identify the start of the explosive push phase (Houdijk etal., 2002). The end of the push phase used to simulate the conventionalhockey skate push was at the instant when the ankle reached an extensionangle 30.5° less than the maximal ankle angle achieved during the actualpush (137°−106.5°=30.5°), that was executed with a klap speed skate. Theend of the push phase used to simulate a hockey skate push with theankle extension conversion was at the instant when the ankle reached anextension angle 15° less than the maximal ankle angle achieved duringthe actual push (137°−122°=15°) that was executed with a klap speedskate.

Maximal ankle extension angle is the factor that affects the pushtermination because beyond 110° of ankle extension the knee joint, eventhough still extending, is producing negative power (absorbing energy)(Houdijk et al., 2002; Van Home & Stefanyshyn). Therefore, the ankle isthe only joint that can continue to contribute and elongate the push. Ifankle extension is stopped the push will be terminated.

Kinetic data were collected with a force platform (Kistler, Winterthur,Switzerland) sampling at 2400 Hz, which was underneath and attached tothe slide board. Kinematic data were collected simultaneously using amultiple video camera system (Motion Analysis Corp., Santa Rosa, Calif.)sampling at 240 Hz. Three reflective markers (1 cm diameter) were placedon each of the boot, the shank and the thigh for kinematic datacollection (FIG. 10). Anthropometric data collected included thesubject's height and mass and were used to determine inertial parametersfrom Clauser et al (1969). Three-dimensional coordinates of each of themarkers were quantified (Expert Vision Analysis, Motion Analysis Corp.,Santa Rosa, Calif.) and the movement within the specific two-dimensionalplanes of interest were then calculated.

A two-dimensional sagittal plane analysis was performed after smoothingboth the video data (fourth-order low-pass Butterworth filter with acutoff frequency of 10 Hz) and the force data (fourth-order low-passButterworth filter with a cutoff frequency of 100 Hz). Resultant jointmoments were determined using inverse dynamics and then used tocalculate joint power by taking the product of the resultant jointmoment and the joint angular velocity (Winter, 1987). Energy wasdetermined by integration of the joint power curve. Energy absorptionoccurs when the resultant joint moment is opposite in direction to theangular velocity. Energy production occurs when the resultant jointmoment is in the same direction as the joint angular velocity. For thisstudy, energy productions at the ankle, knee, and hip joints weredetermined. Paired t-tests (p=0.05) were used to analyze the data forsignificance.

Whole body center of mass positioning and movement were determined fromthe right foot, right shank, right thigh, and torso center of mass (CM)positioning and movement. Pilot testing showed very close agreementbetween this calculation and CM movement determined from whole bodytracking.

Case Studies

Two subjects (proficient hockey players) with similar foot size andshape skated on prototypes of the ankle extension. Frontal view digitalpictures were taken during maximal ankle eversion and inversion with theGraf Supra 703 before and after the ankle extension conversion. Theimages were analyzed for maximal eversion and inversion angles toquantify whether the ankle extension conversion reduced ankle support.Anecdotal accounts were taken for ankle stability qualification.

4. Results and Discussion Angular Energetics And Center Of Mass Movement

There was a significant difference between the simulated final CMvelocity of the push with the conventional hockey skate and the ankleextension skate (FIG. 11). The ankle extension conversion skate had afinal CM velocity of 2.83 (±0.045) m/s. The conventional hockey skatehad a final CM velocity of 2.66 (±0.045) m/s.

The reason for the higher final CM velocity with the ankle extensionconversion skate was that the push took 0.018 seconds longer to execute,which allowed for more energy to be generated at the ankle joint. Thesimulated push with the ankle extension conversion skate producedsignificantly more energy at the ankle (9.67 J) than the conventionalhockey skate (FIG. 12). It should be noted that the increased push timedid not allow for an increase in the knee energy generated becauseduring the final 0.05 seconds of the push the knee does not generatepositive energy (Houdijk et al., 2000; Van Home & Stefanyshyn).

The following example will show the effects of the 0.17 m/s higher CMvelocity, that could potentially be generated with the ankle extensionconversion skate, in an actual hockey game scenario.

Assuming the direction of glide of the pushing skate is at 30° to thelongitudinal direction of the skating path (direction of forward motion)the contribution of the push to forward motion velocity can be easilycalculated (FIG. 13). During the acceleration phase of skating an elitehockey player takes approximately 0.462 seconds per stride (glide phase,push phase, and recovery phase). Therefore, if the push phase for theankle extension conversion skate is 0.018 seconds longer, then a playerusing that skate would take approximately 0.480 seconds per stride.Knowing the time duration of the stride and the acceleration per stride,with certain simplifying assumptions, one could calculate the followingproblem.

Problem: how much faster would Player 1 (wearing the ankle extensionconversion skate) get to a puck that is 12.27 m away than Player 2(wearing a traditional hockey skate)? Assuming both players start from astand still at the exact same position. Also, assuming that both playersare physiologically identical, and their power per stride and stridefrequency remain constant through out the 12.27 m. The problem isanswered in the diagram presented in FIG. 14.

Case Studies

There was no change in maximal eversion and inversion angles of theankle joint when the frontal plane digital still pictures were analyzed(FIG. 15). This indicates that the medial/lateral support was notcompromised with the ankle extension conversion. The anecdotal claimssupport these findings.

5. Comments

The ankle extension allowed for a 15.5° larger range of ankle jointmotion than the traditional hockey skate through increased ankleextension. Through simulations, this increased ankle extension was shownto allow a skater to generate 9.67 J more energy at the ankle jointduring the push phase. This translated into a higher final center ofmass velocity during the push phase. In a hypothetical scenario wheretwo players were racing for a puck 12.27 m away the player with theankle extension skate reached the puck 0.04 seconds sooner than theplayer with traditional hockey skates. A 0.04 second time advantage at avelocity of 8.52 m/s translates into a distance of 34 cm, more thanenough distance to gain control of the puck.

6. Description of the Ankle Extension

The ankle extension is a tendon guard with the addition of a neoprenelower leg strap (FIGS. 1A, 1B, 2A, and 2B). The tendon guard [1] has twocuts [2] angled distally towards the ankle axis of rotation. The twocuts meet approximately 20 mm shy of each other at the point of bending[3]. An elostomeric band [4], that is inserted between the inner andouter layers of the upper and sewn in place, crosses the cut [2] andprovides recoil of the tendon guard [1], after ankle extension. Also toensure adequate recoil of the tendon guard [1] a neoprene lower legstrap [5] is adhered and stitched [6] to the tendon guard. The neoprenestrap [5] fastens to the lower leg by a hook and loop attachment [7], onthe anterior side of the leg (shin).

The advantage of the ankle extension over previous embodiments issimplicity, effectiveness, and comfort. Very little adjustment to thetraditional manufacturing process is needed to build the new skate intoa traditional hockey skate: two cuts and four stitch-lines need to beadded. The new skate allows for increased ankle joint extension withoutany detriment to support or stability. With the addition of the neoprenelower leg strap the wearer feels increased comfort, and the tendon guardstays within a closer proximity to the achilles tendon throughout therange of motion, increasing protection.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

1. A skate boot, comprising: a foot portion configured to receive andsecure a foot of a wearer; an articulating tendon guard positionedproximal an Achilles tendon of the wearer of the skate boot, thearticulating tendon guard being connected to the foot portion at anarticulation point and adjacent the foot portion along a medial abutmentline and a lateral abutment line; and an elastomeric member connected tothe articulating tendon guard and connectable to a lower leg of thewearer; and an elastomeric band connected to the foot portion and to thearticulating tendon guard and configured to bias the articulating tendonguard to a closed position where the articulating tendon guard abuts thefoot portion long the medial abutment line and the lateral abutmentline.
 2. A skate boot, comprising: a foot portion configured to receiveand secure a foot of a wearer; a first tendon guard positioned proximalan Achilles tendon of a wearer of the skate boot, the first tendon guardbeing connected to the foot portion at a first articulation point andadjacent the foot portion along a medial abutment line and a lateralabutment line; a second tendon guard connected to the foot portion at asecond articulation point and to the first tendon guard, the secondtendon guard covering the first articulation point; and an elastomericband connected to the foot portion and to the first tendon guard andconfigured to bias the first tendon guard to a closed position where thefirst tendon guard abuts the foot portion long the medial abutment lineand the lateral abutment line.
 3. An ice skate, comprising: a footportion configured to receive and secure a foot of a wearer; a firsttendon guard positioned proximal an Achilles tendon of the wearer of askate boot, the first tendon guard being connected to the foot portionat a first articulation point and adjacent the foot portion along amedial abutment line and a lateral abutment line; a second tendon guardconnected to the foot portion at a second articulation point andadjacent to the first tendon guard, the second tendon guard covering thefirst articulation point; and an elastomeric band connected to the footportion and to the first tendon guard and configured to bias the firsttendon guard to a closed position where the first tendon guard abuts thefoot portion long the medial abutment line and the lateral abutment linean electrical generator, comprising: a first electrical generationcomponent connected to the first tendon guard; a second electricalgeneration component connected to the second tendon guard, whereinmovement of a leg of the wearer forwards and backwards moves the firstelectrical generation component with respect to the second electricalgeneration component, thereby generating an electrical current; the iceskate connected to the skate boot; and a plurality of resistorsconnected to the ice skate and configured to receive the electricalcurrent from the electrical generator to thereby generate heat and heatthe ice skate.